U.S. farmers wonder how drought will affect grain prices and next year’s crop. A prominent environmentalist’s big-picture take is that the drought is fueling a wave of food unrest worldwide.

“The world is in a transition from an era that’s dominated by surpluses to one that’s increasingly going to be dominated by scarcity,” says Lester Brown, president of the Earth Policy Institute, a Washington, D.C.-based organization that says it’s working for a sustainable future worldwide.

In this new era, “Food is becoming the new oil. Competition for access to food is becoming intense in many cases,” he says.

Brown spoke to reporters in a Sept. 27 conference call. He was promoting his new book, “Full Planet, Empty Plates: The new Geopolitics of Food Scarcity.”

Brown, who has a master’s degree in agricultural economics and once worked for the U.S. Department of Agriculture, is a controversial figure in agricultural circles. He’s warned for decades of a pending global food crisis.

Brown said Sept. 27 that the U.S. drought is worsening an already bad world food situation.

Americans, who spend only 9 percent of their income on food, aren’t impacted greatly by higher food prices brought on by the drought. But higher food prices are devastating for people who spend half or more of their income on food, he said.

Brown said a growing number of families around the world are scheduling “foodless days,” or days on which they don’t eat at all. In Nigeria, he said, 27 percent of families have such days.

Supply and demand

Brown said three factors are affecting world demand for food:

•Population growth, with the world adding nearly 80 million people every year.

•The use of corn for ethanol, which is “squeezing food supplies” both in the United States and overseas.

•Rising affluence overseas, which causes China and other countries to feed much more grain to livestock. “Three billion people in the world are trying to move up the feed chain.”

Brown identified four key factors affecting world food production:

•Water shortages, caused, in part, by overpumping for irrigation. He estimated that roughly 300 million Indians and Chinese are being fed with grain produced by overpumping.

•Global warming, which he said is hurting grain yields.

•Soil erosion, which he said is reducing in some parts of the world.

•A “glass ceiling” on crop yields. For instance, rice yields in Japan haven’t increased for 17 years. While producers want to increase yields, “There are no technologies to take them any further,” he said

Brown said four things are necessary to improve the world’s grain supply-and-demand picture: make more productive use of water, rebuild world grain reserves, stabilize climate by “cutting carbon emissions fast” and stabilize population by eradicating poverty.

Brown will be watching world food prices carefully.

“The price of food, I think, will tell us more about the future of civilization than any other single indicator,” he said.